In a large saucepan over medium heat, melt butter and stir constantly. Butter will begin to foam and boil. After 4 to 5 minutes you will see brown flecks appear in the bottom of the pan. Continue to stir until butter is golden and flecks are a medium brown color. Watch closely, butter will brown quickly. Process will take about 5 to 7 minutes.
Remove butter from heat and add marshmallows, cinnamon, nutmeg, and ginger. Stir until marshmallows are almost completely melted. Add Rice Krispies cereal and stir until evenly coated.
Using a spatula, press cereal mixture firmly into 9x13 pan. Allow to cool completely before cutting into squares.
Recipe can be made without browning the butter to save time. Simply melt your butter, then remove from heat and add your marshmallows as directed.
Rice krispies treats will keep for up to four days in a tightly sealed container at room temperature. Treats are best enjoyed within the first 1-2 days of making.